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Aftermarket Dynamo Lights: a Clean Look

When setting up dynamo lighting on a bicycle with no provisions for it (i.e. no internal routing or special braze-ons), there is always the question of how to route the wiring so that it looks "clean." After all, no one likes to see black wires coiled around a frame's fork and tubes. When setting up the lights on my Rivendell some time ago, the Co-Habitant and I developed a nice method that is practically invisible, and I've been meaning to share it. So when we recently did the same to my Bella Ciao, I made sure to document it.

This method assumes that your bicycle is equipped with fenders, and that you are installing both a headlight and tail light. I will also assume that you already know how to connect the lights themselves; this is not meant to be an electrical tutorial.

The key to our method is using as little wiring as necessary - running it in a straight line parallel to existing stays and tubes, as opposed to coiling it, and securing it with colour-matched zipties. It's a simple idea, but colour-matched zipties really do blend in with the bicycle when all is said and done. You may be surprised to learn that they are available in all sorts of colours - from bright rainbow hues, to neutrals such as clear, white, cream, taupe and gray. We use small gray zipties to route the wire from the tail light along the non-drivetrain side fender chainstay.

In natural light, the result looks like this.

We then proceed along the non-drivetrain side chainstay, using a larger colour-matched ziptie. This frame is a sort of pale military green, and this beige ziptie blends in nicely.

Continuing the same underneath the bottom bracket.

In natural light, the wiring really does "disappear" when routed in this manner, staying close to the chainstay.

If your frame already has shifter cable braze-ons on the downtube as this one does, then you can simply attach the wiring to the shifter cable itself (small black zipties this time). Otherwise, use two large colour-matched zipties for the dwntube, like we did here.

For the headlight, you will need to leave enough wire so that your ability to turn the handlebars is not constricted. We prefer to achieve this by creating a coil here. To do this, simply wrap the wire tightly around a pen or a stick.

And voila, there is your coil. Notice the additional ziptie along the shifter cable, just to keep everything neatly in place.

Finally, use the same colour-matched zipties along the fork as you did along the chainstays, routing the wire to the hub as tautly as possible.

Even frames with internal routing often lack provisions for the fork, and here I find it especially important to find zipties in a colour that blends in with the paint - otherwise it can look as if the fork is cut into pieces, its elegant curvature disturbed. I am using my camera flash to show the process, but in daylight this really looks quite unobtrusive.

In natural light up close.

And from further away.

Having used this method on three bicycles now, I am pleased with it and don't particularly covet frames with provisions for internal routing. Nothing has ever come loose, and visually I am pretty happy with it. You are welcome to use our method, or to share your own.

I have found 25mm wide clear Helicopter tape (aka 3M Polyurethane Protective Tape) to be useful in some situations eg instead of the zipties on the fork I use a few pieces of this thick tape and it is effectively invisible in use.

I also use the tape on either side of my top tube to protect the paint finish when leaning it against anything. A piece on the drive-side chainstay protects against chain slap.

Amy - The tail light is by a German company called Buechel, they are not sold in the US as far as I know. This is the same light I chose for the Bella Ciao "Superba" (except that frame was built with provisions for internal routing).

This is a great post. If you have a bike with no lighting, you can pick up a German-made Busch and Muller Dymotec 6 for around $55, carefully mount it and route the wires and have what looks like factory lighting.Affordable Luxury Blog

I just completed an internal wiring job that I'm proud of. I went up through the center of the fork, out through a hole I drilled through the fork that lines up with the down tube, then through the down tube, around the bottom bracket and up the seat tube, and finally out through a hole I drilled in the seat post. Both holes are protected by grommets and there is enough play in the down tube wire so that when I turn the front wheel the wire just follows along. There is a gap of at least a few mm between the fork tube and the head tube so there is no interference with turning. It works well and looks neat.

Hobbes vs Boyle - It's not the colour coordination I care about, but the wiring or its attachment not disrupting the lines of the bike. In that sense, the neutral ties work quite well. As for the wiring itself, it being black does not bother me, provided it is not coiled around the tubing.

Masmojo - Good idea, though I suspect it would change the scope/ difficulty level of the project for most people : )

Jon Webb - You drilled it yourself? That is impressive; could be worth providing a tutorial on your site. How did you deal with preventing rust, etc?

Yeah, especially holes on the upper end of the downtube tend to be a problem. I've seen quite a number of frames in Germany where cracks developed from those wholes (internal cable routing is/was pretty common even with lower end bikes in Germany).

Your method is very clean and nice, but on a custom bike, I would not dismiss internal wiring.

Internal wiring is great when it's done well. On my new bike, the only wire exposed is at the generator hub, and if I used the "connectorless" SON hub, I could eliminate that.

The advantage goes far beyond the clean appearance. The wires never will get snagged or otherwise compromised, no matter where I park my bike or who handles it when it's shipped via Amtrak.

Poorly done internal wiring is a maintenance nightmare, when something goes wrong. But done well, that isn't a concern. My house also has internal wiring, and I am not constantly ripping out the plaster to fix it...

Pot of water (preferably one you don't plan on using to make food), Dump in dye, warm to near boiling and throw the ties in for 5 or so minutes, rinse, DONE! For this application you could probably even do it in a micro wave! May not match exactly, but close then a stock color of zip tie!

It was a carbon/alloy fork, so I just measured where the hole should go and drilled, same with the seat post. No corrosion because nothing is made from steel -- the frame is titanium and anyway I'm not creating any new ways in for water. Both holes are grommeted and the wire is a tight fit.

BTW, I drilled through the fork so I could avoid drilling the frame, voiding the warranty on the frame and causing all those problems people like Ground Round Jim warn about. The fork between the lower and upper bearing is not carrying any load to speak of and I had a hard time imagining drilling a hole in it would cause a problem. But anyway, a new fork isn't outrageously expensive, and the frame warranty is intact, as is the frame.

Jan - Oh I am not dismissing an expertly made frame with internal routing. But not everyone has that option; buying a stock frame with no provisions for wiring is the more likely scenario for most of my readers and this is one method I suggest for that situation.

Love those BC bikes . . . just the right amount of sturdiness / utility.

Have you tried mounting any B&M lights with the mounting hardware similar to what is shown in the photos on bikes with cantilever brakes? I recently purchased on and found it difficult to attach it to the fender bolt area without an overly long bolt. It was difficult to get the beam pointing straight ahead. I finally moved it to RH fork braze on. This was a cleaner and more solid mounting point, but it still required an extra long bolt and spacer to clear the brakes and much of the beam was cut off by the wheel.

Another option for when there are no provisions for internal wiring is to run the wire externally along the main tubes (as you showed) but then along the underside of the rear fender instead of along the stay. That's how I did it on my Shogun after the wiring exits the bottom bracket. The wire can just be glued in place at several points.

Seems like a Sharpy (available in many colors) would also work for coloring zip-ties. If you're really picky, you'll pick zipties that are UV proof (some are, some are not).

My wires are currently a bit of a mess up around the front end, but otherwise they just run alongside all the other continuous cables (shift and brake) to the back of the bike. To reduce the front mess, I wrap wires in continuous two-sided velcro wrap (one step up from the stuff you use for binding plants to trellises). I'd love to figure out the internal runs, but thus far that is beyond my capacity for planning and taking the bike out of service. It does seem plausible with the threadless fork that I could arrange to hide most of the wires and route them into inconspicuous places. What I'd really love to do, is redo the electronics in a form that I could stuff up inside the steerer tube.

I use marine-grade wires because I hate messing with maintenance and decay.

Good topic! Another option is to route the wire through the rolled edge of the fender instead of along the stay or under the fender. I posted a couple of photos:http://www.flickr.com/photos/27089900@N00/6304846387/in/photostream-Vélocia

Wire isn't something one thinks about often, but the right wire can actually have a positive aesthetic impact. Think of it as potential, instead of as something to hide.

Have you ever heard of Sundial Wire? They produce cloth-covered wire (both cotton and rayon) like you would find on vintage appliances. Beneath the cloth is modern PVC insulation, so there's no risk of shorting out in the rain. Shellacking cloth-covered wire like bar tape might be an interesting experiment, though.

Check out their site; some of their products are downright lovely: http://www.sundialwire.com/clothcoveredwire.aspx

Also, keep in mind that electrical resistance increases in proportion to conductor length, so short wire runs make for a more efficient system (and better component life). Using a thicker conductor (i.e. a lower gauge number) helps minimize resistance too.

Also, having experience in electronics design, I'm not so sure coiling the wire is the best idea. By coiling wire, you create a rudimentary inductor. The light bulb is a resistor. Putting the two in series in the same circuit increases the peak current in the wire, which hurts efficiency and can be bad for both the bulb and the voltage regulator in the dynamo. For the technically-minded, here's a page explaining how this happens: http://www.ndt-ed.org/EducationResources/CommunityCollege/EddyCurrents/Physics/impedance.htm

A more "conventional" solution would be to leave just enough slack in the wire to let the wheel turn, provide cable guides (zip ties loose enough to let the wire slide along its axis work fine) to prevent the slack from getting caught on anything, and use strain relief boots or bushings at the ends of the wire. A cable sheath where the wire is expected to flex most may help too. And, of course, use stranded wire when flex is expected.

Instead of zip ties you can do a quick whip with hemp twine or some other type of string. The natural color of hemp twine is good for earth toned bikes, and it would probably be easy to dye it or get string in a different color if needed. Twine whippings have the advantage of not having a little piece that sticks out and catches things the way the nub of a zip tie does.

I was lucky to get your Bella Ciao bike, and I've been happily riding it for over a year. But yesterday my front bulb burned out. I can't figure out how to open the light to be able to replace the bulb. Any suggestions? Thanks a lot, especially for the great design!

I've had good luck routing the wiring along the top and down tubes, using a bonded two-wire cable (like speaker wire, but smaller-- we're not powering a house, here) routed through Jagwire brake cable housing. I route up from the bottom bracket generator (which I use on 3 different bikes, 2 Sanyos and a Union)along the seat tube thence to the taillight; I slot a V-brake noodle to give a portal to the wire coming out to the taillight, mounted on the NDS seatstay right by the seatpost clamp. The remaining length of wire get routed along the top of the tube in its own length of brake cable housing, down the head tube with another noodle, and out to the headlamp at the fork crown with yet another noodle and a short coil to give it slack. On two bikes,I use standard Dia-Compe 1" cable clips along the top tube and 1-1/8 clamps on the seat tube. One at the base and one at the top of the ST, and then 3 down the length of the top tube. On the bikes with brazeons for the rear cable on the top tube, I just route right alongside and it looks quite sanitary. The other bike lacks the clips so I found some Shimano clips designed to clamp 2 cables, at about the 4 and 8 o'clock positions on the underside of the top tube, and used those: One for the brake, another for the wire. The short length of housing in between the noodles on the head tube I secured with color-matched zip ties. I tried using a contrasting color and a larger tie, but in the end, it looked aesthetically questionable, so I got a good match to the medium grey and went with it.

How do I get the wire down the cable? Shop air and a needle end. Works great, just get the wire started and give it enough slack and blow. It'll come through eventually.

Ultraviolet light in sunlight damages the plastic in zip ties. The black ones are are generaly safe from damage because they contain carbon black pigment that absorbes the UV. Other colors could be a problem. Intense colors that contain titanium dioxide pigment would probably ok too,

Has anyone ever taped the wire along the length of the fork on the inside using a long wide strip of electrical tape or that clear "helicopter" surface guard tape? I have a carbon fiber fork, and am trying to come up with a way of securing the wire to the inside of the fork without concern for snags while retaining the outer appearance of the fork leg, and thought I might give that a try.

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